Research on the natural purification capacity in a river exihibiting large seasonal change

Abstract

This paper discussed the water quality, water quality model and natural purification capacity as well as their seasonal characteristics in Tumenjiang River, flowing through China, North Korea and Russia into Japan Sea. Following conclusions were obtained:
1. There were found good correlations between CODcr, BOD5 and CODMn in the river water polluted by the wastewater from the pulp and paper mill.
2. The water quality model applicable to the mid-reaches of the River was introduced, including seasonal change of the natural purification capacity.
3. By utilizing the purification capacity efficiently, it was recommended to construct a stock lagoon and to store a part of the wastewater in winter, low-water season and discharge it in the period of high-water. The treatment cost required for this process was estimated to be 46 Chinese yuan (930yen)/ton pulp, and 209 Chinese yuan/t·p will be saved than that for the wastewater treatment of 60% cut corresponding to the present standared in China.
This study will be useful to “Tumenjiang Development Project” organized by UNDP.